Safety of and serum antibody response to cold-recombinant influenza A and inactivated trivalent influenza virus vaccines in older adults with chronic diseases

Influenza vaccine for chronic obstructive pulmonary disease (COPD)

BACKGROUND

Influenza vaccinations are currently recommended in the care of people with COPD, but these recommendations are based largely on evidence from observational studies, with very few randomised controlled trials (RCTs) reported. Influenza infection causes excess morbidity and mortality in people with COPD, but there is also the potential for influenza vaccination to cause adverse effects, or not to be cost effective.

OBJECTIVES

To determine whether influenza vaccination in people with COPD reduces respiratory illness, reduces mortality, is associated with excess adverse events, and is cost effective.

SEARCH METHODS

We searched the Cochrane Airways Trials Register, two clinical trials registries, and reference lists of articles. A number of drug companies we contacted also provided references. The latest search was carried out in December 2017.

SELECTION CRITERIA

RCTs that compared live or inactivated virus vaccines with placebo, either alone or with another vaccine, in people with COPD.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. All entries were double-checked. We contacted study authors and drug companies for missing information. We used standard methods expected by Cochrane.

MAIN RESULTS

We included 11 RCTs with 6750 participants, but only six of these included people with COPD (2469 participants). The others were conducted on elderly and high-risk individuals, some of whom had chronic lung disease. Interventions compared with placebo were inactivated virus injections and live attenuated intranasal virus vaccines. Some studies compared intra-muscular inactivated vaccine and intranasal live attenuated vaccine with intra-muscular inactivated vaccine and intranasal placebo. Studies were conducted in the UK, USA and Thailand.Inactivated vaccine reduced the total number of exacerbations per vaccinated participant compared with those who received placebo (mean difference (MD) -0.37, 95% confidence interval (CI) -0.64 to -0.11; P = 0.006; two RCTs, 180 participants; low quality evidence). This was due to the reduction in 'late' exacerbations, occurring after three or four weeks (MD -0.39, 95% CI -0.61 to -0.18; P = 0.0004; two RCTs, 180 participants; low quality evidence). Both in people with COPD, and in older people (only a minority of whom had COPD), there were significantly more local adverse reactions in people who had received the vaccine, but the effects were generally mild and transient.There was no evidence of an effect of intranasal live attenuated virus when this was added to inactivated intramuscular vaccination.Two studies evaluating mortality for influenza vaccine versus placebo were too small to have detected any effect on mortality. However, a large study (N=2215) noted that there was no difference in mortality when adding live attenuated virus to inactivated virus vaccination, AUTHORS' CONCLUSIONS: It appeared, from the limited number of RCTs we were able to include, all of which were more than a decade old, that inactivated vaccine reduced exacerbations in people with COPD. The size of effect was similar to that seen in large observational studies, and was due to a reduction in exacerbations occurring three or more weeks after vaccination, and due to influenza. There was a mild increase in transient local adverse effects with vaccination, but no evidence of an increase in early exacerbations. Addition of live attenuated virus to the inactivated vaccine was not shown to confer additional benefit.

Protecting pediatric oncology patients from influenza

Influenza is a common respiratory pathogen. Its severity can be unpredictable, but people with chronic illness are at increased risk of severe infection, complications, and death from influenza. This review examines evidence to support various strategies to protect pediatric oncology patients from influenza-related morbidity. Influenza vaccination should be considered standard. Additional evidence-supported measures include antiviral treatment, antiviral prophylaxis, cohorting of patients, and hospital infection control measures. Data from other high-risk populations support the vaccination of family members, double-dose or high-dose vaccination, and the use of barrier methods. These measures have the potential to optimize patient outcomes because there will be fewer treatment interruptions for acute illness. These strategies can also protect patients from prolonged hospitalizations and morbidity related to influenza.

Influenza vaccine for patients with chronic obstructive pulmonary disease

BACKGROUND

Influenza vaccinations are currently recommended in the care of people with COPD, but these recommendations are based largely on evidence from observational studies with very few randomised controlled trials (RCTs) reported. Influenza infection causes excess morbidity and mortality in COPD patients but there is also the potential for influenza vaccination to cause adverse effects or not to be cost effective.

OBJECTIVES

To evaluate the evidence from RCTs for a treatment effect of influenza vaccination in COPD subjects. Outcomes of interest were exacerbation rates, hospitalisations, mortality, lung function and adverse effects.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register of trials, and reference lists of articles. References were also provided by a number of drug companies we contacted.

SELECTION CRITERIA

RCTs that compared live or inactivated virus vaccines with placebo, either alone or with another vaccine in persons with COPD. Studies of people with asthma were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. All entries were double checked. Study authors and drug companies were contacted for missing information.

MAIN RESULTS

Eleven trials were included but only six of these were specifically performed in COPD patients. The others were conducted on elderly and high-risk individuals, some of whom had chronic lung disease. Inactivated vaccine in COPD patients resulted in a significant reduction in the total number of exacerbations per vaccinated subject compared with those who received placebo (weighted mean difference (WMD) -0.37, 95% confidence interval -0.64 to -0.11, P = 0.006). This was due to the reduction in "late" exacerbations occurring after three or four weeks (WMD -0.39, 95% CI -0.61 to -0.18, P = 0.0004). In Howells 1961, the number of patients experiencing late exacerbations was also significantly less (odds ratio 0.13, 95% CI 0.04 to 0.45, P = 0.002). Both Howells 1961 and Wongsurakiat 2004 found that inactivated influenza vaccination reduced influenza -related respiratory infections (WMD 0.19, 95% CI 0.07 to 0.48, P = 0.0005). In both COPD patient and in elderly patients (only a minority of whom had COPD), there was a significant increase in the occurrence of local adverse reactions in vaccinees, but the effects were generally mild and transient. There was no evidence of an effect of intranasal live attenuated virus when this was added to inactivated intramuscular vaccination. The studies are too small to have detected any effect on mortality. An updated search conducted in September 2001 did not yield any further studies. A search in 2003 yielded two further reports of the same eligible study Gorse 2003. A search in 2004 yielded two reports of the another eligible study Wongsurakiat 2004. The author informed us of another report of the same study Wongsurakiat 2004/2.

AUTHORS' CONCLUSIONS

It appears, from the limited number of studies performed, that inactivated vaccine reduces exacerbations in COPD patients. The size of effect was similar to that seen in large observational studies, and was due to a reduction in exacerbations occurring three or more weeks after vaccination, and due to influenza. There is a mild increase in transient local adverse effects with vaccination, but no evidence of an increase in early exacerbations.

Universal vaccination of healthy children against influenza: a role for the cold-adapted intranasal influenza vaccine

The incidence of influenza in children well exceeds that of the elderly and has been identified as the basis for 20% of doctor visits for children during the winter. The disease results in over 100 hospitalizations per 100000 person-months in children <2 years of age. Furthermore, children serve as the major vector in the community; thus, influenza in children results in significant costs to society. Although efficacious, the current intramuscular, inactivated influenza vaccine is infrequently used in children, and is currently targeted only at children at high risk and those who are household members of such individuals. Experts believe that vaccinating only high risk individuals has little impact on the cycle of annual epidemics, but that universal vaccination of children may very well have a substantial impact. Experimental data support this. A recently published cost-benefit analysis indicated that routine, school-aged vaccination through individual visits to a clinician would save 4 US dollars per child vaccinated. A group program such as a school-based one would save 35 US dollars. One obstacle to universal vaccination includes the real and perceived resistance to the addition of yet another annual injection to the already crowded schedule of routine childhood immunizations. Nearing licensure is an intranasal, live attenuated, cold-adapted intranasal influenza vaccine. Cold-adaptation prevents replication in the lower respiratory tract. Trials have demonstrated immunogenicity, safety, and tolerability in adults as well as children. Placebo-controlled trials have shown efficacy rates of 83 to 94%. This novel vaccine addresses obstacles to universal childhood immunization and would permit a program of routine use that would dramatically reduce transmission and stem epidemics of influenza.

Cold-adapted live influenza vaccine versus inactivated vaccine: systemic vaccine reactions, local and systemic antibody response, and vaccine efficacy. A meta-analysis

Since the 1940s, influenza vaccines are inactivated and purified virus or virus subunit preparations (IIV) administered by the intramuscular route. Since decades, attempts have been made to construct, as an alternative, attenuated live influenza vaccines (LIV) for intranasal administration. Presently, the most successful LIV is derived from the cold-adapted master strains A/Ann Arbor/6/60 (H2N2) and B/Ann Arbor/1/66 (AA-LIV, for Ann-Arbor-derived live influenza vaccine). It has been claimed that AA-LIV is more efficacious than IIV. In order to assess differences between the two vaccines with respect to systemic reactogenicity, antibody response, and efficacy, we performed a meta-analysis on eighteen randomised comparative clinical trials involving a total of 5000 vaccinees of all ages. Pooled odds ratios (AA-LIV versus IIV) were calculated according to the random effects model. The two vaccines were associated with similarly low frequencies of systemic vaccine reactions (pooled odds ratio: 0.96, 95% confidence interval: 0.74-1.24). AA-LIV induced significantly lower levels of serum haemagglutination inhibiting antibody and significantly greater levels of local IgA antibody (influenza virus-specific respiratory IgA assayed by ELISA in nasal wash specimens) than IIV. Yet, although they predominantly stimulate different antibody compartments, the two vaccines were similarly efficacious in preventing culture-positive influenza illness. In all trials assessing clinical efficacy, the odds ratios were not significantly different from one (point of equivalence). The pooled odds ratio for influenza A-H3N2 was 1.50 (95% CI: 0.80-2.82), and for A-H1N1, 1.03 (95% CI: 0.58-1.82). The choice between the two vaccine types should be based on weighing the advantage of the attractive non-invasive mode of administration of AA-LIV, against serious concerns about the biological risks inherent to large-scale use of infectious influenza virus, in particular the hazard of gene reassortment with non-human influenza virus strains.

Immunogenicity and efficacy of Russian live attenuated and US inactivated influenza vaccines used alone and in combination in nursing home residents

The immunogenicity and efficacy of Russian live attenuated and US inactivated trivalent influenza vaccines administered alone or in three different combinations were evaluated in a randomized, placebo-controlled, double-blinded study of 614 elderly or chronically ill nursing home residents in St. Petersburg, Russia during the 1996-97 influenza season. Postvaccination serum antibody responses were more frequent among individuals administered the combination vaccines than among those vaccinated with live or inactivated vaccine alone. Only individuals who received live vaccine, alone or in combination with inactivated vaccine, achieved significant postvaccination increases in virus-specific nasal IgA. Efficacy in preventing laboratory-confirmed influenza in vaccinated versus nonvaccinated individuals was 67% (95%CI, 36-81%) for recipients of a combination of the vaccines compared with 51% (95%CI, -17-79%) for recipients of live vaccine alone and 50% (95%CI, -26-80%) for recipients of inactivated vaccine alone. These results suggest that administration of a combination of influenza vaccines may provide a strategy for improved influenza vaccination of elderly people.

Influenza vaccine for patients with chronic obstructive pulmonary disease

BACKGROUND

Influenza vaccinations are currently recommended in the care of people with COPD, but these recommendations are based largely on evidence from observational studies with very few randomised controlled trials (RCTs) reported. Influenza infection causes excess morbidity and mortality in COPD patients but there is also the potential for influenza vaccination to cause adverse effects or not to be cost effective.

OBJECTIVES

To evaluate the evidence from RCTs for a treatment effect of influenza vaccination in COPD subjects. Outcomes of interest were exacerbation rates, hospitalisations, mortality, lung function and adverse effects.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register and reference lists of articles. References were also provided by a number of drug companies we contacted.

SELECTION CRITERIA

RCTs that compared live or inactivated virus vaccines with placebo, either alone or with another vaccine in persons with COPD. Studies of people with asthma were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data. All entries were double checked. Study authors and drug companies were contacted for missing information.

MAIN RESULTS

Nine trials were included but only four of these were specifically performed in COPD patients. The others were conducted on elderly and high-risk individuals, some of whom had chronic lung disease. In one study of inactivated vaccine in COPD patients there was a significant reduction in the total number of exacerbations per vaccinated subject compared with those who received placebo (weighted mean difference (WMD) -0.45, 95% confidence interval -0.75 to -0.15, p = 0.004). This difference was mainly due to the reduction in exacerbations occurring after 3 weeks (WMD -0.44, (95% CI -0.68 to -0.20, p<0.001). The number of patients experiencing late exacerbations was also significantly less (OR= 0.13, 95%CI 0.04 to 0.45, p=0.002). There was no evidence of an effect of intranasal live attenuated virus when this was added to inactivated intramuscular vaccination. In studies in elderly patients (only a minority of whom had COPD), there was a significant increase in the occurrence of local adverse reactions in vaccinees, but the effects were generally mild and transient.

REVIEWER'S CONCLUSIONS

It appears, from the limited number of studies performed, that inactivated vaccine may reduce exacerbations in COPD patients. The size of effect was similar to that seen in large observational studies, and was due to a reduction in exacerbations occurring three or more weeks after vaccination. In elderly, high risk patients there was an increase in adverse effects with vaccination, but these are seen early and are usually mild and transient.

Control of influenza in the long-term-care facility: a review of established approaches and newer options

Influenza infections pose a serious threat to residents of nursing homes and other long-term-care facilities. Annual vaccination of residents and staff with the currently licensed inactivated influenza vaccine continues to be the mainstay of prevention. Live attenuated influenza vaccine, which is expected to be licensed in the United States in the near future, may offer added protection for elderly persons when administered in conjunction with inactivated vaccine. Antiviral agents also can be useful as an adjunct to vaccination, especially for control of institutional outbreaks. Two new antiviral agents that appear to be less toxic than amantadine and rimantadine have recently been approved.

Prevention of influenza in long-term-care facilities. Long-Term-Care Committee of the Society for Healthcare Epidemiology of America

Influenza is a frequent cause of epidemic and endemic respiratory illness in long-term-care facilities (LTCFs), resulting in considerable morbidity and mortality. Detection of influenza outbreaks in this setting can be difficult, because the clinical presentation in older adults is atypical and other pathogens also cause influenza-like illness (ILI) during the influenza season. Use of the standard case definition for influenza has not been effective in detecting episodes in residents of LTCFs. Alternative case-definitions that reflect the atypical presentation of influenza in this population have been recommended but not validated. The use of rapid tests for the detection of influenza in conjunction with more sensitive case definitions of ILI may lead to the earlier detection of influenza outbreaks in LTCFs, earlier initiation of infection control measures, and reduction in transmission. The definition of outbreak, eg, the number of episodes of ILI or episodes of confirmed influenza A that would result in the initiation of antiviral chemoprophylaxis, remains controversial in this setting. The use of newer antivirals could limit the side effects seen in older adults in LTCFs. However, annual vaccination of residents and staff remains the most effective way to prevent the introduction of influenza A or influenza B into LTCFs. In addition, vaccination of LTCF residents reduces rates of illness and pneumonia due to influenza, as well as cardiopulmonary exacerbation, hospitalization, and death.

Is there a role for a mucosal influenza vaccine in the elderly?

Influenza infection is an acute respiratory disease with a high morbidity and significant mortality, particularly among the elderly and individuals with chronic diseases. The majority of countries now recommend annual influenza vaccination for all people aged 65 years or older, and for those with high risk conditions. Most commercially available influenza vaccines are administered systemically and while these are effective in children and young adults, efficacy levels in elderly individuals have been reported to be much lower. Mucosal vaccines may offer an improved vaccine strategy for protection of the elderly. As the influenza virus causes a respiratory infection, it is potentially more beneficial to administer a vaccine that will boost protection in the mucosal surfaces of the upper and lower respiratory tract. Mucosal influenza vaccines are aimed at stimulating protective immunity in the respiratory tract via oral or intranasal immunisation. This review examines our present knowledge of mucosal immunity and current strategies for mucosal vaccination. It also stresses that the use of serum antibody levels as a 'surrogate marker' for protection against influenza is potentially misleading; serum antibody, for example, may be a quite inappropriate marker to assess a mucosal vaccine. This marker does not reflect other immune responses to vaccination that are crucial for protection.

Influenza virus vaccination of patients with chronic lung disease

STUDY OBJECTIVES

To evaluate the safety of, and mucosal and systemic immune responses induced by two influenza virus vaccine regimens in subjects with COPD.

DESIGN

Single-center, blinded, randomized, prospective clinical trial evaluating two vaccine regimens.

SETTING

Outpatient clinics of St. Louis Department of Veterans Affairs Medical Center.

PARTICIPANTS

Volunteers (age range, 42 to 88 years) had preexisting COPD with severe obstruction to airflow on average, were male, and were not receiving immunosuppressive medication.

INTERVENTIONS

Twenty-nine volunteers were randomly assigned to receive either bivalent live attenuated influenza A virus vaccine (CAV) or saline solution placebo intranasally. All subjects also received an i.m. injection of trivalent inactivated influenza virus vaccine (TVV) simultaneously.

MEASUREMENTS AND RESULTS

Clinical status and pulmonary function measured by spirometry did not change significantly after vaccination. Using hemagglutinins (H1 and H3 HA) which more closely resembled those in CAV, mean levels of anti-HA immunoglobulin A (IgA) antibodies in nasal washings increased significantly after vaccination with CAV and TVV compared to prevaccination, but they did not increase significantly after TVV and intranasal placebo. Mean levels of influenza A virus-stimulated interleukin-2 and -4 produced by peripheral blood mononuclear cells in vitro increased significantly after administration of the combination vaccine regimen and to a lesser extent after TVV and intranasal placebo compared to respective prevaccination levels. The timing of the cytokine response appeared different following CAV and TVV compared to TVV and intranasal placebo.

CONCLUSIONS

Intranasally administered CAV was safe when given with i.m. administered TVV and there may be an immunologic advantage to administration of the combination vaccine regimen compared to TVV with intranasal placebo.

Superiority of live attenuated compared with inactivated influenza A virus vaccines in older, chronically ill adults

Forty-eight older adults with chronic diseases were vaccinated intranasally with live attenuated influenza A/Korea/1/82 (H3N2), CR59 virus. Forty-two (88 percent) CR59 virus recipients became infected with vaccine virus without adverse effects or change in mean pulmonary function even among the 29 infected recipients with moderate to severe chronic obstructive pulmonary disease. Among control groups who received either monovalent or trivalent inactivated influenza virus vaccines intramuscularly, the rates of fourfold rises in serum antibody titer to hemagglutinin (HA) were not different from the rate following CR59 virus inoculation. However, CR59 virus was superior to inactivated virus vaccine at stimulating secretory antibody to HA. Vaccinees age 65 years and older were more likely to shed CR59 virus in nasal secretions than were younger vaccinees, but antibody responses were not different. CR59 virus vaccine was safe and immunogenic in this population and more often induced a nasal wash IgA antibody response than the inactivated virus vaccines.

In elderly persons live attenuated influenza A virus vaccines do not offer an advantage over inactivated virus vaccine in inducing serum or secretory antibodies or local immunologic memory

In a double-blind, randomized trial, 102 healthy elderly subjects were inoculated with one of four preparations: (i) intranasal bivalent live attenuated influenza vaccine containing cold-adapted A/Kawasaki/86 (H1N1) and cold-adapted A/Bethesda/85 (H3N2) viruses; (ii) parenteral trivalent inactivated subvirion vaccine containing A/Taiwan/86 (H1N1), A/Leningrad/86 (H3N2), and B/Ann Arbor/86 antigens; (iii) both vaccines; or (iv) placebo. To determine whether local or systemic immunization augmented mucosal immunologic memory, all volunteers were challenged intranasally 12 weeks later with the inactivated virus vaccine. We used a hemagglutination inhibition assay to measure antibodies in sera and a kinetic enzyme-linked immunosorbent assay to measure immunoglobulin G (IgG) and IgA antibodies in sera and nasal washes, respectively. In comparison with the live virus vaccine, the inactivated virus vaccine elicited higher and more frequent rises of serum antibodies, while nasal wash antibody responses were similar. The vaccine combination induced serum and local antibodies slightly more often than the inactivated vaccine alone did. Coadministration of live influenza A virus vaccine did not alter the serum antibody response to the influenza B virus component of the inactivated vaccine. The anamnestic nasal antibody response elicited by intranasal inactivated virus challenge did not differ in the live, inactivated, or combined vaccine groups from that observed in the placebo group not previously immunized. These results suggest that in elderly persons cold-adapted influenza A virus vaccines offer little advantage over inactivated virus vaccines in terms of inducing serum or secretory antibody or local immunological memory. Studies are needed to determine whether both vaccines in combination are more efficacious than inactivated vaccine alone in people in this age group.

Enhanced lymphoproliferation to influenza A virus following vaccination of older, chronically ill adults with live-attenuated viruses

To question whether cellular immunity was stimulated by live-attenuated viruses in older, chronically ill adults, we intranasally inoculated 2 groups of volunteers (n = 37) with 2 different cold-recombinant, live-attenuated influenza A virus vaccines, and measured peripheral blood mononuclear cell responsiveness to influenza antigens and mitogen before and after vaccination. Lymphocyte proliferation to vaccine virus and to heterosubtypic influenza A virus increased postvaccination even in the subpopulation of vaccines who had a 4-fold nasal wash antibody titer rise to vaccine virus hemagglutinin, but no concomitant serum antibody titer rise to hemagglutinin. Vaccines aged greater than or equal to 65 years exhibited a rise in proliferation to vaccine virus postvaccination, as well. Based on lymphocyte proliferation, vaccine virus infection induced an enhanced cell-mediated immune response. Higher prevaccination serum antibody titers, however, were associated with protection from vaccine virus infection, and higher lymphocyte proliferation was not.

Enhancement of anti-influenza A virus cytotoxicity following influenza A virus vaccination in older, chronically ill adults

We studied anti-influenza cytotoxicity by bulk peripheral blood mononuclear leukocyte (PBL) cultures derived from older, chronically ill volunteers undergoing vaccination. Vaccinees received either cold-recombinant, live-attenuated influenza A/Korea/1/82 (H3N2) virus intranasally or inactivated monovalent influenza A/Taiwan/1/86 (H1N1) subvirion vaccine intramuscularly. PBL were collected pre- and postvaccination and in vitro stimulated by autologous PBL infected with influenza A virus homologous and heterosubtypic to the respective vaccine strain. Cytotoxicity was measured against influenza A virus-infected autologous and human leukocyte antigen (HLA)-mismatched PBL targets infected with influenza A virus homologous or heterosubtypic to the vaccine virus strain. Vaccinees infected with the live-attenuated virus developed significant rises in mean anti-influenza, HLA-restricted cytotoxicity that was cross-reactive against influenza A viruses homologous and heterosubtypic to the vaccine virus. The enhanced cross-reactive cytotoxicity was inducible postvaccination by in vitro stimulation with autologous PBL infected with the homologous influenza A (H3N2) virus and with influenza A (H1N1) virus. In contrast, after vaccination with inactivated monovalent subvirion vaccine, volunteers developed significant increases in mean anti-influenza, HLA-restricted cytotoxicity only against autologous PBL infected with homologous influenza A (H1N1) virus. Increased cytotoxicity occurred only after in vitro stimulation with autologous cells infected with homologous influenza A (H1N1) virus. Mean gamma interferon levels in supernatant fluids of influenza A virus-stimulated effector PBL did not increase postvaccination, despite increased levels of anti-influenza cytotoxicity displayed by the effector cells. We conclude that the live-attenuated influenza A virus infection induced a broader range of enhanced anti-influenza cytotoxicity than did the inactivated subvirion vaccine.

Influenza: status and prospects for its prevention, therapy, and control

This article describes current knowledge of the molecular properties of orthomyxoviruses, their epidemiology, and approaches to the control of influenza. The host's response to infection, approaches to prevent infection through vaccination, and the use of antiviral agents to treat or prevent this important infection are covered.

Use of live cold-adapted influenza A H1N1 and H3N2 virus vaccines in seropositive adults

To investigate the immunogenicity and protective efficacy of cold-adapted influenza vaccine in individuals with underlying immunity to influenza A virus, we administered cold-adapted H1N1 and H3N2 vaccines to adults with prevaccination serum hemagglutination inhibition antibody titers of 1:16 or more and challenged them 1 month afterwards with homologous wild-type influenza A virus. Both cold-adapted vaccines were immunogenic in seropositive adults. In addition, individuals receiving cold-adapted vaccines had lower rates of virus shedding and illness following challenge with wild-type influenza virus than did unvaccinated seropositive volunteers.

Systemic and local antibody responses in elderly subjects given live or inactivated influenza A virus vaccines

Intranasal live attenuated cold-adapted (ca) influenza A/Kawasaki/9/86 (H1N1) reassortant virus and parenteral inactivated influenza A/Taiwan/1/86 (H1N1) virus were given alone or in combination to 80 ambulatory elderly subjects. An enzyme-linked immunosorbent assay was used to measure hemagglutinin-specific (HA) antibodies in serum and nasal wash specimens collected before vaccination and 1 and 3 months later. Serum immunoglobulin G (IgG) and nasal wash IgA HA responses were elicited in 56 and 20%, respectively, of 25 inactivated-virus vaccinees and in 67 and 48%, respectively, of 27 recipients of both vaccines but in only 36 and 25%, respectively, of 28 vaccinees given live virus alone. Inactivated virus, administered alone or with live virus vaccine, induced higher titers of serum antibody than did the live virus alone. In contrast, nasal IgA HA antibody was elicited more often and in greater quantity by the vaccine combination than by either vaccine alone. Despite these differences, the peak titers of local antibody mounted by each group of vaccinees were similar. By 3 months postvaccination, serum IgG and nasal IgA HA antibody titers remained elevated above prevaccination levels in 50 and 17%, respectively, of the inactivated-virus vaccinees and in 46 and 23%, respectively, of recipients of both vaccines but in only 19 and 7%, respectively, of the live-virus and systemic antibodies, if vaccinees. The finding that live ca influenza A virus induced short-lived local and systemic antibodies, if confirmed, suggests that live virus vaccination may not be a suitable alternative or adjunct to inactivated virus vaccination for the elderly.

Evaluation of cold-recombinant influenza A/Korea (CR-59) virus vaccine in infants

Twenty-four infants 5 to 13 months of age were intranasally vaccinated with a live cold-recombinant influenza A/Korea (CR-59, H3N2) virus vaccine. Nineteen infants served as controls. The inocula ranged from 10(3.2) to 10(6.2) 50% tissue culture infective doses (TCID50) per infant. Zero of six, one of four, seven of ten, and four of four infants receiving 10(3.2), 10(4.2), 10(5.2), and 10(6.2) TCID50, respectively, were infected by the intranasal vaccine. The amount of virus required to infect 50% of infants was calculated to be 10(4.6) TCID50. The occurrence of fever, respiratory illness, and otitis media was common among both controls and vaccinees in the postinoculation period. Maternal antibody was present in low titers in some infants and did not inhibit replication of the vaccine virus.

Analysis of virus and host factors in a study of A/Peking/2/79 (H3N2) cold-adapted vaccine recombinant in which vaccine-associated illness occurred in normal volunteers

Live attenuated cold-adapted influenza vaccine is undergoing evaluation in man. Several strains have proven to be safe, immunogenic, nontransmissible, and protective against experimental challenge. In this study of A/Peking/2/79(H3N2), with six internal genes from the cold-adapted (Ca) parent A/Ann Arbor/6/60(H2N2), we encountered at the highest input multiplicity, 28% illness rate among individuals infected with vaccine. Reversion to wild type and excessive viral replication did not occur. Physical characteristics of the vaccine were similar to nonreactogenic vaccine A/Washington/897/80(H3N2). At ten- and 100-fold lower input multiplicities, infection frequency was maintained, but reactions did not occur. We compared the observations in this study with those made in a similar study of A/Scotland/840/74(H3N2), a cold-adapted vaccine with five genes from the Ca parent in which reactogenicity also was noted. The dose of vaccine virus in relation to tissue culture infectious doses required to infect 50% of susceptibles (HID50) was proportionally lower for both A/Peking/2/79(H3N2) and A/Scotland/80(H3N2). Hence, when the vaccine was undiluted the recipients were inoculated with more than 100 HID50. We concluded that the very high input could be avoided if vaccines were screened beginning at 1/1,000 of maximum titers. Ca vaccines must be safe before they undergo field trials.

Local and systemic antibody responses in high-risk adults given live-attenuated and inactivated influenza A virus vaccines

Forty seropositive older adults with chronic diseases were vaccinated intranasally with either influenza A/California/10/78 (H1N1) (CR37) or influenza A/Washington/897/80 (H3N2) (CR48) virus. No clinically significant decrements in pulmonary function occurred postvaccination. Eight (62%) recipients of CR37 virus and 16 (59%) recipients of CR48 virus became infected with vaccine virus, as indicated by a fourfold rise in nasal wash immunoglobulin G (IgG) or IgA antibody titer, a fourfold rise in serum antibody titer, isolation of vaccine virus from nasal washings, or all of these. Within 2 years after cold-recombinant virus vaccination, 29 vaccinees received trivalent inactivated influenza virus vaccine parenterally. After inactivated virus vaccination, 23 (79%) vaccinees developed a fourfold rise in nasal wash or serum antibody titer to H1 antigen and 24 (83%) developed a fourfold rise in nasal wash or serum antibody titer to H3 antigen. Significantly more cold-recombinant virus vaccinees developed a fourfold rise in nasal wash IgA antibody to H1 or H3 hemagglutinin compared with inactivated virus vaccinees (17 [43%] versus 9 [17%], P = 0.01). We conclude that these cold-recombinant virus vaccines are safe and immunogenic in seropositive older high-risk adults and more often induced a nasal wash IgA antibody response than the inactivated virus vaccine.